Data rates are increasing, in part due to increasing demand for communication bandwidth. Advanced technologies may provide high-speed data rates; however, power consumption for such high-speed signals can be significant. For example, clock distribution power in high-speed serial link systems may be considerable as clocking frequency increases to support high data rates. Conventionally, a clock signal may be sourced from a common clock source. This common clock source may be distributed or routed over a long distance across an IC. Routing a high frequency clock signal over a significant distance can consume a significant amount of power. This power consumption has become an increasingly significant issue with increased frequencies to support high data rate systems.
Additionally, serial link systems may support multiple communication specifications (“multi-standard serial link systems”) with a single crystal oscillator. More recently, integer-N phase-locked loops (“PLLs”) may be dedicated to provide clock frequencies used by various communication specifications in such multi-standard serial link systems. However, use of integer-N PLLs may involve having different crystal oscillators for PLL reference clock signal inputs, for supporting different frequencies of different communication specifications. Furthermore, having discrete frequency ranges, as in a conventional integer-N PLL multi-standard serial link system, may limit flexibility with respect to having a discontinuous data rate range covered by such frequency ranges.
While LC-tank oscillators are known to have low phase noise, such LC-tank oscillators conventionally consume large amounts of semiconductor area, and their tuning range may be limited by their quality factor. On the other hand, ring voltage controlled oscillators can provide a wide frequency range, but their phase noise performance may not be adequate for high performance applications.
Accordingly, it would be desirable and useful to provide a clock generator for a receiver that overcomes or mitigates one or more of the above-described limitations.